The nuclear option

EDITORIAL, TNNApr 2, 2005, 01.51am IST

What price nuclear power? It is pertinent to ask, now that the newest unit of India's oldest nuclear power plant has gone critical, in Tarapur.

TAPP-4 is also our largest and first 540 MW atomic plant. It has been built in record time, too. And once TAPP-3 goes critical, soon, nuclear power capacity pan-India would add up to 3,850 MW. It's a mere 3% of our current installed power base, true.

But the upside can be huge, if we can get the economics right. TAPP-3&4, at 1,080 MW capacity, reportedly costs Rs 6,500 crore, on the high side compared to capital expenditure (capex) for conventional coal-fired thermal plants.

But operating costs are, typically, no more than 10% of capex in nuclear plants; opex for thermal stations can be up to 80% of capex. Fission reactors using uranium and heavy water are the simplest of nuclear reactors.

But there are serious roadblocks to the availability of fissile material. Given the very limited uranium reserves, our nuclear power capacity using pressurised heavy water reactors (PHWR) can add up to a maximum of perhaps 10,000 MW.

The way ahead is to recycle and reprocess the spent fuel to get plutonium-based material for use in fast breeder reactors (FBR). More importantly, we need to make use of our massive reserves of thorium to generate nuclear power.

Fuel-grade uranium is obtained by irradiating thorium in PHWRs and FBRs. One estimate suggests our thorium reserves can support 3,00,000 MW of power, for the next 300 years! But given the control regime for things nuclear, the first indigenously built FBR is expected only in 2011.

A small 40 MW test FBR is indeed functional in Kalpakkam, since 1985. Also, the design of a prototype FBR of 500 MW capacity is reportedly ready. And pre-project activities have included the manufacture of full-scale components.

Concurrently, to expedite the transition to thorium-based systems, an advanced heavy water reactor (AHWR) is in the works.

Reportedly, the AHWR is being designed to generate 75% power from thorium. It could wholly transform the power scenario. Let there be light!